lnflistener.java

java swing 开发代码

// LnFListener.java
// A listener that can change the look-and-feel of a frame based on
// the actionCommand of an ActionEvent object. Supported look-and-feels are:
//   Mac, Metal, Motif, Windows.
// Not all L&Fs will be available on a given machine. Notably, the Mac and
// Windows L&Fs work only on their specific platforms.
package	jswing.ch02;

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class LnFListener implements ActionListener {
  Frame frame;

  public LnFListener(Frame f) {
    frame = f;
  }

  public void actionPerformed(ActionEvent e) {
    String lnfName = null;
    if (e.getActionCommand().equals("Mac")) {
      lnfName = "com.apple.mrj.swing.MacLookAndFeel";
    } else if (e.getActionCommand().equals("Metal")) {
      lnfName = "javax.swing.plaf.metal.MetalLookAndFeel";
    } else if (e.getActionCommand().equals("Motif")) {
      lnfName = "com.sun.java.swing.plaf.motif.MotifLookAndFeel";
    } else if (e.getActionCommand().equals("Windows")) {
      lnfName = "com.sun.java.swing.plaf.windows.WindowsLookAndFeel";
    } else {
      System.err.println("Unrecognized L&F request action: " +
        e.getActionCommand()); 
      return;
    }
    try {
      UIManager.setLookAndFeel(lnfName);
      SwingUtilities.updateComponentTreeUI(frame);
    }
    catch (UnsupportedLookAndFeelException ex1) {
      System.err.println("Unsupported LookAndFeel: " + lnfName);
    }
    catch (ClassNotFoundException ex2) {
      System.err.println("LookAndFeel class not found: " + lnfName);
    }
    catch (InstantiationException ex3) {
      System.err.println("Could not load LookAndFeel: " + lnfName);
    }
    catch (IllegalAccessException ex4) {
      System.err.println("Cannot use LookAndFeel: " + lnfName);
    }
  }
}